1. Field
The present application relates generally to wireless communications, and more specifically to systems and methods to enable associated access terminals to acquire an access point (AP) base station, while preventing other access terminals from attempting to acquire the AP base station.
2. Background
Wireless communication systems are widely deployed to provide various types of communication (e.g., voice, data, multimedia services, etc.) to multiple users. As the demand for high-rate and multimedia data services rapidly grows, there lies a challenge to implement efficient and robust communication systems with enhanced performance. These systems may include multiple-access systems capable of supporting communication with multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, and Frequency Division Multiple Access (FDMA) systems. A CDMA system may implement a radio access technology (RAT) such as cdma2000 or Wideband-CDMA (W-CDMA). cdma2000 covers the well-known IS-2000, IS-856, and IS-95 standards.
IS-2000 and IS-95 support both voice and data services and are commonly referred to as “1x-EV-DV”, or simply “1x”, where the DV stands for “data and voice”. A wireless device (e.g., a cellular phone) supporting 1x typically maintains a preferred roaming list (PRL). The PRL contains information to assist the wireless device perform system selection and acquisition on 1x systems, particularly when the wireless device is roaming. The PRL identifies “permitted” systems that the wireless device should use and (optionally) “forbidden” systems that the wireless device should not use. The PRL format for 1x systems is described in a document TIA/EIA/IS-683-A, entitled “Over-the-Air Service Provisioning of Mobile Stations in Spread Spectrum Standards,” June 1998, which is publicly available.
IS-856 supports packet data service and is commonly referred to as “1xEV-DO”, where the DO stands for “data optimized”. A wireless device supporting 1xEV-DO also maintains a PRL for system selection and acquisition on 1xEV-DO systems. The PRL format for 1xEV-DO is described in a document TIA/EIA/IS-683-C, entitled “Over-the-Air Service Provisioning of Mobile Stations in Spread Spectrum Standards,” Oct. 25, 2002, which is also publicly available. IS-683-C describes (1) a PRL format that is an updated version of the PRL format defined by IS-683-A and that may be used for 1× systems and (2) an extended PRL format that may be used for both 1x and 1xEV-DO systems.
For 1x and 1xEV-DO, a wireless device maintains a PRL for system selection and acquisition. The wireless device may be programmed with the PRL via a serial interface, a Universal Serial Bus (USB) interface, or some other type of interface, e.g., during manufacturing or activation. The wireless device may also obtain the PRL via over-the-air signaling or from a Removable User Identity Module (R-UIM), which is a removable module that can be inserted into the wireless device. The wireless device may store the PRL in a non-volatile memory so that the PRL is retained even when power is turned off. The non-volatile memory may be located within the wireless device or in the removable module.
Such PRLs, whether pre-installed or deployed to wireless devices, include information that controls which base stations of the systems/networks the wireless devices may associate with. Base station (1x terminology) refers to a fixed station and may also be called a base transceiver station (BTS), an access point (1xEV-DO terminology), a Node B (W-CDMA terminology), or some other terminology. It is noted that a wireless device may also be called a mobile station (1x terminology), a user/access terminal or AT/HAT (1xEV-DO terminology), a user equipment (UE) (W-CDMA terminology), a mobile equipment (ME) (also W-CDMA terminology), a handset, a subscriber unit, or some other terminology.
Recently, a new class of small base stations has emerged, which may be installed in a user's home and provide indoor wireless coverage to mobile units using existing broadband Internet connections. Such a personal miniature base station is generally known as an access point (AP) base station, also referred to as Home Node B (HNB) unit, femto cell, femto base station (fBS), base station, or some other terminology. Typically, such AP base stations are connected to the Internet and the mobile operator's network via a digital subscriber line (DSL) router or cable modem, and allow for small scale network environments, also referred to as a femto network (i.e., a network of AP base stations or femto cells).
AP base stations allow for cellular access where coverage from normal base station support from a macro network (i.e., a network of non-femto cells) is weak or unavailable (e.g., indoors, remote locations, and the like). AP base stations may be described as small base stations that connect to wireless service providers via a broadband backhaul link, such as digital subscriber line (DSL), cable internet access, T1/T3, etc., and offer typical base station functionality, such as base transceiver station (BTS) technology, radio network controller, and gateway support node services. This allows a wireless device, referred to herein as an access terminal (AT), to connect to the AP base stations and utilize the wireless service. It is noted that ATs can include, for example, cellular phones, smart phones, laptops, handheld communication devices, handheld computing devices, satellite radios, navigational devices, PDAs, and/or any other suitable device for communicating over a wireless communication system.
An owner of an AP base station will typically limit access to his/her AP base station to those ATs associated with the AP base station, such as, for example, his/her AT and those ATs that he/she has specifically granted access to. Sometimes, a visitor AT (i.e., an AT that is not associated with any AP base stations, or an AT that is not currently in the coverage area of its associated AP base station) may enter the coverage area of a given AP base station it is not associated with. In certain situations, the visitor AT may repeatedly make attempts to acquire the AP base station despite the fact that it is not authorized to operate on the AP base station. Accordingly, there is a need for a technique for programming or adapting the AT to attempt acquisition of AP base stations that it is authorized to use, while refraining from attempting acquisition of other AP base stations that it is not authorized to use.